This invention relates to a method and apparatus for analyzing the product flowing from a kiln, or like instrumentality, with information obtained from the analysis being usable to automatically produce adjustments in the operating conditions of the kiln, and to perform other functions such as directing of the flow of product from the kiln to different storage facilities where different types of product are collected.
In a more specific sense, the invention is directed to a method and apparatus for controlling the degree to which a material is sintered in a rotary kiln, or similar apparatus, in order that the material being process not be either overburned or underburned. By way of example, in the production of Portland Cement clinker, the raw material from which the clinker is produced commonly is heated in a continuous rotary kiln with raw material introduced at one end and the burned clinker product flowing from the other end of the kiln. During the burning of the product in the kiln, various chemical reactions take place which have the effect of changing the porosity of the material being processed. Thus, it has been conventional in the past in controlling the operation of such a kiln to obtain a sample from the kiln and to obtain the weight of a measured volume of the sample, which is indicative of the quality of the clinker produced and also indicative of whether kiln operating conditions should be changed in order to obtain optimum properties in the clinker produced.
While it has been known in the past that density measurements of clinker material produced in a kiln are useful in controlling kiln operation and performing other functions, the usual manner of making such measurements has relied upon manual procedures for collecting and weighing a sample. Such a system has not been entirely reliable by reason of variables introduced because of different persons performing the testing. More importantly, information obtained is at relatively infrequent and nonregular intervals, meaning that it is not suitable for close control of kiln operation. Furthermore, such a procedure does not lend itself for incorporation with an automatic or semiautomatic control system for controlling kiln operation, or the directing of material from a kiln to a specific silo or storage facility, nor does it promote the continuous recording of information pertaining to operating conditions which are usable by a manufacturer in obtaining over a period of time maximum production efficiencies and the production of a uniform and quality product.
A general object of this invention, therefore, is to provide a novel means and method for monitoring the product produced in a sintering operation, such as a kiln, which on a regular and periodic basis establishes automatically data usable in controlling kiln operation.
A related object is to provide such a means and method which is highly reliable and consistent.
Yet a further object of the invention is to provide means and method for monitoring product produced by a kiln which relies upon the diversion from the output of a kiln of a sample flow of material and the processing of this sample and while flowing as induced by gravity to produce a measured volume of material having a particle size within a predetermined range which is electronically weighed, with weight and time information then recorded.
The material which is diverted to form the sample flow of material after processing to obtain the information desired is returned to the kiln operator's transport system, then to be directed by the system to an appropriate storage site such as a silo.
Following the invention and when used with a kiln producing clinker material, a record may be maintained of clinker densities at regular time intervals. The production of a consistent product is enhanced by the continuous feeding of density and timing information to the control center for the kiln. Manpower costs incurred in weighing and recording selected samples are eliminated; production costs may be reduced. Mill performance is improved by and through the maintenance of records indicating product type in any storage facility or silo involved.